mirror of
https://github.com/italicsjenga/valence.git
synced 2024-12-25 07:11:31 +11:00
231 lines
7.3 KiB
Rust
231 lines
7.3 KiB
Rust
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use std::io::Write;
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use byteorder::{BigEndian, WriteBytesExt};
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use zerocopy::AsBytes;
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use crate::tag::Tag;
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use crate::{Compound, Error, List, Result, Value, MAX_DEPTH};
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/// Encodes uncompressed NBT binary data to the provided writer.
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///
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/// Only compounds are permitted at the top level. This is why the function
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/// accepts a [`Compound`] reference rather than a [`Value`].
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///
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/// Additionally, the root compound can be given a name. Typically the empty
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/// string `""` is used.
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pub fn to_binary_writer<W: Write>(writer: W, compound: &Compound, root_name: &str) -> Result<()> {
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let mut state = EncodeState { writer, depth: 0 };
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state.write_tag(Tag::Compound)?;
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state.write_string(root_name)?;
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state.write_compound(compound)?;
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debug_assert_eq!(state.depth, 0);
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Ok(())
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}
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struct EncodeState<W> {
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writer: W,
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/// Current recursion depth.
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depth: usize,
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}
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impl<W: Write> EncodeState<W> {
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#[inline]
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fn check_depth<T>(&mut self, f: impl FnOnce(&mut Self) -> Result<T>) -> Result<T> {
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if self.depth >= MAX_DEPTH {
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return Err(Error::new_static("reached maximum recursion depth"));
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}
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self.depth += 1;
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let res = f(self);
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self.depth -= 1;
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res
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}
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fn write_tag(&mut self, tag: Tag) -> Result<()> {
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Ok(self.writer.write_u8(tag as u8)?)
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}
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fn write_value(&mut self, v: &Value) -> Result<()> {
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match v {
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Value::Byte(b) => self.write_byte(*b),
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Value::Short(s) => self.write_short(*s),
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Value::Int(i) => self.write_int(*i),
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Value::Long(l) => self.write_long(*l),
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Value::Float(f) => self.write_float(*f),
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Value::Double(d) => self.write_double(*d),
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Value::ByteArray(ba) => self.write_byte_array(ba),
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Value::String(s) => self.write_string(s),
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Value::List(l) => self.check_depth(|st| st.write_any_list(l)),
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Value::Compound(c) => self.check_depth(|st| st.write_compound(c)),
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Value::IntArray(ia) => self.write_int_array(ia),
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Value::LongArray(la) => self.write_long_array(la),
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}
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}
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fn write_byte(&mut self, byte: i8) -> Result<()> {
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Ok(self.writer.write_i8(byte)?)
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}
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fn write_short(&mut self, short: i16) -> Result<()> {
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Ok(self.writer.write_i16::<BigEndian>(short)?)
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}
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fn write_int(&mut self, int: i32) -> Result<()> {
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Ok(self.writer.write_i32::<BigEndian>(int)?)
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}
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fn write_long(&mut self, long: i64) -> Result<()> {
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Ok(self.writer.write_i64::<BigEndian>(long)?)
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}
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fn write_float(&mut self, float: f32) -> Result<()> {
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Ok(self.writer.write_f32::<BigEndian>(float)?)
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}
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fn write_double(&mut self, double: f64) -> Result<()> {
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Ok(self.writer.write_f64::<BigEndian>(double)?)
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}
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fn write_byte_array(&mut self, bytes: &[i8]) -> Result<()> {
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match bytes.len().try_into() {
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Ok(len) => self.write_int(len)?,
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Err(_) => {
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return Err(Error::new_owned(format!(
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"byte array of length {} exceeds maximum of i32::MAX",
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bytes.len(),
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)))
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}
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}
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Ok(self.writer.write_all(bytes.as_bytes())?)
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}
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fn write_string(&mut self, s: &str) -> Result<()> {
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let s = cesu8::to_java_cesu8(s);
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match s.len().try_into() {
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Ok(len) => self.writer.write_u16::<BigEndian>(len)?,
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Err(_) => {
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return Err(Error::new_owned(format!(
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"string of length {} exceeds maximum of u16::MAX",
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s.len()
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)))
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}
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}
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Ok(self.writer.write_all(&s)?)
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}
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fn write_any_list(&mut self, list: &List) -> Result<()> {
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match list {
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List::Byte(bl) => {
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self.write_tag(Tag::Byte)?;
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match bl.len().try_into() {
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Ok(len) => self.write_int(len)?,
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Err(_) => {
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return Err(Error::new_owned(format!(
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"byte list of length {} exceeds maximum of i32::MAX",
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bl.len(),
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)))
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}
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}
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Ok(self.writer.write_all(bl.as_bytes())?)
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}
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List::Short(sl) => self.write_list(sl, Tag::Short, |st, s| st.write_short(*s)),
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List::Int(il) => self.write_list(il, Tag::Int, |st, i| st.write_int(*i)),
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List::Long(ll) => self.write_list(ll, Tag::Long, |st, l| st.write_long(*l)),
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List::Float(fl) => self.write_list(fl, Tag::Float, |st, f| st.write_float(*f)),
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List::Double(dl) => self.write_list(dl, Tag::Double, |st, d| st.write_double(*d)),
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List::ByteArray(bal) => {
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self.write_list(bal, Tag::ByteArray, |st, ba| st.write_byte_array(ba))
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}
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List::String(sl) => self.write_list(sl, Tag::String, |st, s| st.write_string(s)),
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List::List(ll) => {
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self.check_depth(|st| st.write_list(ll, Tag::List, |st, l| st.write_any_list(l)))
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}
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List::Compound(cl) => self
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.check_depth(|st| st.write_list(cl, Tag::Compound, |st, c| st.write_compound(c))),
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List::IntArray(ial) => {
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self.write_list(ial, Tag::IntArray, |st, ia| st.write_int_array(ia))
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}
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List::LongArray(lal) => {
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self.write_list(lal, Tag::LongArray, |st, la| st.write_long_array(la))
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}
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}
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}
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fn write_list<T, F>(&mut self, list: &Vec<T>, elem_type: Tag, mut write_elem: F) -> Result<()>
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where
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F: FnMut(&mut Self, &T) -> Result<()>,
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{
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self.write_tag(elem_type)?;
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match list.len().try_into() {
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Ok(len) => self.writer.write_i32::<BigEndian>(len)?,
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Err(_) => {
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return Err(Error::new_owned(format!(
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"{elem_type} list of length {} exceeds maximum of i32::MAX",
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list.len(),
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)))
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}
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}
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for elem in list {
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write_elem(self, elem)?;
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}
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Ok(())
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}
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fn write_compound(&mut self, c: &Compound) -> Result<()> {
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for (k, v) in c.iter() {
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self.write_tag(Tag::element_type(v))?;
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self.write_string(k)?;
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self.write_value(v)?;
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}
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self.write_tag(Tag::End)?;
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Ok(())
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}
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fn write_int_array(&mut self, ia: &[i32]) -> Result<()> {
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match ia.len().try_into() {
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Ok(len) => self.write_int(len)?,
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Err(_) => {
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return Err(Error::new_owned(format!(
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"int array of length {} exceeds maximum of i32::MAX",
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ia.len(),
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)))
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}
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}
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for i in ia {
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self.write_int(*i)?;
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}
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Ok(())
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}
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fn write_long_array(&mut self, la: &[i64]) -> Result<()> {
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match la.len().try_into() {
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Ok(len) => self.write_int(len)?,
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Err(_) => {
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return Err(Error::new_owned(format!(
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"long array of length {} exceeds maximum of i32::MAX",
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la.len(),
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)))
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}
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}
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for l in la {
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self.write_long(*l)?;
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}
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Ok(())
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}
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}
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